Photodynamic antibacterial fiber membrane as well as preparation method and application thereof

Abstract

The invention discloses a photodynamic antibacterial fiber membrane and a preparation method and application thereof, and relates to the field of functional materials.The preparation method comprises the steps that aggregation-induced emission photosensitive molecules are dissolved in a first solvent, and a photosensitive molecule solution is obtained; dissolving the purified polymer in a second solvent, and adding a photosensitive molecular solution to obtain a spinning precursor solution; adjusting and controlling the orientation degree of the spinning precursor solution through electrostatic spinning to obtain a fiber membrane; adjusting and controlling the crystallinity of the fiber membrane to obtain the photodynamic antibacterial fiber membrane. According to the preparation method provided by the invention, a polymer condensed state structure is combined with aggregation-induced emission photosensitive molecules, and a rigid confinement domain is provided for the photosensitive molecules by utilizing polymer crystallization and an orientation structure; meanwhile, the contact area between the material and oxygen is increased by utilizing the nanoscale of the electrostatic spinning fiber membrane, and the active oxygen yield of the material is synergistically improved.

Description

Technical Field

[0001] The present application relates to the field of functional materials, and in particular to a photodynamic antibacterial fiber membrane and a preparation method and application thereof. Background Art

[0002] Photodynamic antibacterial uses the reactive oxygen species generated by photosensitizers under light irradiation to destroy the bacterial structure to achieve sterilization. Compared with the traditional method of using antibiotics for antibacterial, photodynamic antibacterial has the advantages of high spatiotemporal selectivity, non-invasiveness, no drug resistance and broad-spectrum sterilization. For photodynamic antibacterial, the selection of photosensitizers is crucial. Organic photosensitizers are widely used because of their wider wavelength absorption capacity, stronger tissue penetration ability, higher selectivity and better biocompatibility. However, traditional organic photosensitizers such as porphyrins and phthalocyanines have a planar rigid π-conjugated structure, which is easy to cause fluorescence quenching effect (Aggregation-Caused Quenching, ACQ) in the aggregated state, which often needs to be prevented by some carrier encapsulation. In contrast, aggregation-induced emission (AIE) molecules can solve the ACQ problem well, because AIE molecules usually have a highly twisted structure and rich rotation and vibration movements. In the aggregated state, non-radiative decay pathways are blocked, which increases the probability of single excited states and subsequent intersystem crossing (ISC) processes, thereby facilitating more energy to be used in the generation of reactive oxygen species.

[0003] In order to further enhance the photodynamic therapy effect of AIE photosensitizers, a restricted microenvironment is often provided by designing a rigid structure, which is mainly used to restrict the intramolecular motion of AIE molecules to increase their reactive oxygen production rate. However, as a polymer matrix, fiber can easily obtain orientation and crystal structure during the processing and manufacturing process, and can provide a rigid restricted structure for the molecule; secondly, because it has a large surface area, it is conducive to the large-area distribution of photosensitizers and large-area contact with the surrounding environment, further improving the efficiency of photodynamic therapy. At the same time, due to the fixation of the photosensitizer by the fiber structure, it can also play a certain sustained release role and extend the service life of the antibacterial material. At present, there are two main forms of fiber used as a photosensitive molecule carrier: one is to directly dip the personal protective equipment fabric into the photosensitive molecule; the other is to electrospin the photosensitizer and polymer into a nanofiber membrane after blending.

[0004] However, existing studies have only simply mixed the photosensitizer molecules with polymers or directly attached the molecules to the fabric, which may have problems such as weak restriction effect or easy elution of the photosensitizer molecules, resulting in low active oxygen production. Summary of the invention

[0005] In order to solve the above-mentioned technical problems existing in the prior art, the present application provides a photodynamic antibacterial fiber membrane and its preparation method and application, so as to overcome the technical problems in the prior art such as low active oxygen yield of photodynamic antibacterial fabrics, easy elution of photosensitive molecules, and poor photostability.

[0006] In order to achieve the above purpose, the technical solution of the embodiment of the present application is:

[0007] The first aspect of the present application provides a method for preparing a photodynamic antibacterial fiber membrane, comprising:

[0008] dissolving aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution;

[0009] Dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution;

[0010] The spinning precursor solution is oriented and regulated by electrostatic spinning to obtain a fiber membrane;

[0011] The crystallinity of the fiber membrane is regulated to obtain a photodynamic antibacterial fiber membrane.

[0012] In combination with the first aspect, preferably, the polymer is L-polylactic acid, and the structural formula of the L-polylactic acid is:

[0013]

[0014] In combination with the first aspect, preferably, the structural formula of the aggregation-induced luminescence photosensitive molecule is:

[0015]

[0016] In combination with the first aspect, preferably, the first solvent is one or more of dimethyl sulfoxide and N,N-dimethylformamide; and / or, the second solvent is one or more of chloroform and dichloromethane.

[0017] In combination with the first aspect, preferably, the content of the polymer in the spinning precursor solution is 8-12wt%; the content of the aggregation-induced emission photosensitive molecules in the spinning precursor solution is 1-2wt%.

[0018] In combination with the first aspect, preferably, the volume ratio of the first solvent to the second solvent is 1:4.

[0019] In combination with the first aspect, preferably, the orientation degree regulation by electrospinning includes: the spinning voltage is 18-22 kV, the propulsion speed is 0.8-1.2 mL / h, the receiving distance from the needle to the roller is 14-16 cm, the receiving speeds of the roller are 300 rpm, 600 rpm, and 900 rpm respectively, and the spinning time is 3h-4h.

[0020] In combination with the first aspect, preferably, when the crystallinity is regulated, the crystallization temperature is 125-130° C., and the crystallization time is 0 min, 30 min, 60 min and 90 min.

[0021] The second aspect of the present application provides a photodynamic antibacterial fiber membrane as described in the first aspect.

[0022] The third aspect of the present application provides an application of the photodynamic antibacterial fiber membrane prepared by the method of the first aspect or the photodynamic antibacterial fiber membrane of the second aspect in the preparation of polymer materials.

[0023] Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application include at least:

[0024] The preparation method provided in the present application, on the one hand, combines the polymer condensed state structure with the aggregation-induced luminescence photosensitive molecules, and uses the polymer crystallization and orientation structure to provide a rigid confined domain for the photosensitive molecules; on the other hand, the nanoscale of the electrospun fiber membrane is used to increase the contact area between the material and oxygen, and synergistically improve the active oxygen yield of the material to obtain a fiber membrane material with high-efficiency photodynamic antibacterial properties; thirdly, compared with traditional materials that use antibiotics for antibacterial purposes, it can effectively circumvent bacterial resistance, and at the same time has the advantages of high spatiotemporal selectivity, non-invasiveness, and spectral sterilization.

[0025] The photodynamic antibacterial fiber membrane prepared in the present application, which can regulate the polymer condensed structure and increase the active oxygen yield of photosensitizer molecules, can be used as a material for air purification, personal protection and photodynamic wound dressing, and has a certain light stability. After being recycled 10 times, the active oxygen yield of the material can still be maintained at almost the initial level. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the preparation process of the photodynamic antibacterial fiber membrane provided in the embodiment of the present application;

[0027] Figure 2 The scanning electron microscope images and orientation distribution diagrams of the antibacterial fiber membranes with different orientation degrees prepared in Example 1;

[0028] Figure 3 The scanning electron microscope images and diameter statistics of the antibacterial fiber membranes with different orientation degrees prepared in Example 1 at a receiving drum speed of 900 rpm;

[0029] Figure 4 This is a characterization diagram of the crystallinity of the photodynamic antibacterial fiber membrane at different isothermal crystallization times in Example 2;

[0030] Figure 5The water contact angle diagram of the photodynamic antibacterial fiber membrane of Example 2 at a receiving drum speed of 900 rpm and after isothermal crystallization for 0 min and 90 min respectively;

[0031] Figure 6 The singlet oxygen yield data of the photodynamic antibacterial fiber membrane of Example 2 after the receiving drum speed is 900 rpm and the isothermal crystallization is performed for 0 min and 90 min respectively;

[0032] Figure 7 This is a data graph of singlet oxygen yield of the photodynamic antibacterial fiber membrane of Example 2 when the receiving drum speed is 900 rpm, the isothermal crystallization is 90 min, and the irradiation is repeated 11 times;

[0033] Figure 8 This is a characterization diagram of the antibacterial effect of pure electrospun fiber membrane, antibacterial fiber membrane with a receiving roller speed of 300 rpm without isothermal crystallization treatment, and antibacterial fiber membrane with a 90-min isothermal crystallization treatment and a receiving roller speed of 900 rpm on Staphylococcus aureus and Escherichia coli. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0035] In the following description, reference is made to "some embodiments", which describe a subset of all possible embodiments, but it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of the present application have the same meaning as those commonly understood by those skilled in the art of the technical field of the embodiments of the present application. The terms used in the embodiments of the present application are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0036] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are all open terms, meaning including but not limited to.

[0037] It should be noted that all raw materials / reagents in the examples of the present application can be purchased on the market or prepared according to conventional methods well known to those skilled in the art; the term "and / or" in the examples of the present application is only used to describe the association relationship between associated objects, indicating that three relationships may exist, for example, A and / or B means the existence of A alone, B alone, and A and B at the same time, among which A and B can be singular or plural, and the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0038] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0039] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0040] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0041] Those skilled in the art will appreciate that the numerical ranges in the examples of the present application are to be understood as also specifically disclosing each intermediate value between the upper and lower limits of the range. Each smaller range between the intermediate values ​​in any stated value and stated range and any other stated value or intermediate value in the range is also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0042] Unless otherwise stated, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art in the field described in the present application. Although the present application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the embodiments or test cases of the present application. All documents mentioned in this specification are generally incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of the present application shall prevail.

[0043] It should be noted that all raw materials and / or reagents in the examples of the present application are purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0044] In a first aspect, an embodiment of the present application provides a method for preparing a photodynamic antibacterial fiber membrane, the preparation method comprising:

[0045] dissolving aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution;

[0046] Dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution;

[0047] The spinning precursor solution is oriented and regulated by electrostatic spinning to obtain a fiber membrane;

[0048] The crystallinity of the fiber membrane is regulated to obtain a photodynamic antibacterial fiber membrane.

[0049] The preparation method provided in the embodiments of the present application, on the one hand, combines the polymer condensed state structure with the aggregation-induced luminescence photosensitive molecules, and uses the polymer crystallization and orientation structure to provide a rigid confined domain for the photosensitive molecules; on the other hand, the nanoscale of the electrospun fiber membrane is used to increase the contact area between the material and oxygen, and synergistically improve the active oxygen yield of the material to obtain a fiber membrane material with high-efficiency photodynamic antibacterial properties; thirdly, compared with traditional materials that use antibiotics for antibacterial purposes, it can effectively circumvent bacterial resistance, and at the same time has the advantages of high spatiotemporal selectivity, non-invasiveness, and spectral sterilization.

[0050] Figure 1 Schematic diagram of the preparation process of the photodynamic antibacterial fiber membrane provided in the embodiment of the present application. Figure 2 The scanning electron microscope images and orientation distribution diagrams of the antibacterial fiber membranes with different orientation degrees prepared in Example 1.

[0051] In a specific embodiment, the polymer in the embodiment of the present application is preferably L-polylactic acid, and the structural formula of L-polylactic acid is preferably:

[0052]

[0053] The embodiment of the present application selects the L-polylactic acid of this structural formula because its unique semi-crystalline structure and oriented structure provide a rigid confined domain for the photosensitive molecules.

[0054] In a specific embodiment, the structural formula of the aggregation-induced emission photosensitizer (DPA-SCP) in the embodiment of the present application is preferably:

[0055]

[0056] The embodiment of the present application selects the aggregation-induced luminescence photosensitizer of this structure because its twisted molecular structure can avoid the problem of low reactive oxygen yield caused by aggregation quenching of traditional photosensitizers with planar rigid π conjugated structures. At the same time, the photosensitive molecule is cleverly designed with α-cyanostilbene as the AIE skeleton and diphenylamine as a strong electron donor, and a strong electron donor-acceptor part is designed, so that an AIE luminescent source with wide color tunability in the visible light range can be obtained, thereby achieving a white light-driven photodynamic sterilization effect. At the same time, the positive ions of the pyridinium salt are conducive to anchoring bacteria (most of the bacterial surfaces are negatively charged), which is beneficial to its antibacterial effect.

[0057] It should be noted that the present application regulates the orientation and crystallinity of the polymer by means of electrospinning and isothermal crystallization to enhance the active oxygen yield of the photosensitive molecules. At the same time, the nanofiber structure is used to increase the oxygen contact area and maintain the photostability of the photosensitizer, thereby further improving the photodynamic antibacterial efficiency of the fiber membrane.

[0058] In a specific embodiment, the first solvent in the embodiment of the present application is preferably one of dimethyl sulfoxide and N,N-dimethylformamide.

[0059] It should be noted that the first solvent is a high boiling point solvent.

[0060] In a specific embodiment, the second solvent in the embodiment of the present application is preferably one of chloroform and dichloromethane.

[0061] It should be noted that the second solvent is a low boiling point solvent.

[0062] In a specific embodiment, the content of the polymer in the spinning precursor solution in the embodiment of the present application is preferably 8-12 wt %; the content of the aggregation-induced emission photosensitizer molecules in the spinning precursor solution is preferably 1-2 wt %.

[0063] Among them, when the polymer content in the spinning precursor is less than 8wt%, the polymer molecular chains in the spinning precursor lack sufficient entanglement and cannot form a continuous electrostatic jet, and fibers with beads will be obtained, thereby affecting the fiber morphology; when the polymer content in the spinning precursor is greater than 12wt%, the fiber diameter will become coarser and cannot be maintained at the nanometer level, and the uniformity of the fiber will also deteriorate.

[0064] In a specific embodiment, the volume ratio of the first solvent to the second solvent in the embodiment of the present application is preferably 1:4.

[0065] Among them, when the volume ratio of the first solvent and the second solvent is less than 1:4, since the second solvent is a low-boiling point solvent, when its content increases, the overall boiling point of the spinning precursor will be lowered, which can easily cause needle clogging during the spinning process; when the volume ratio of the first solvent and the second solvent is greater than 1:4, since the first solvent has a low solubility in the polymer, it will cause partial precipitation of the polymer and affect the uniformity of the spinning precursor.

[0066] In a specific embodiment, the orientation degree control by electrospinning in the embodiment of the present application is preferably: the spinning voltage is 18-22 kV, the propulsion speed is 0.8-1.2 mL / h, the receiving distance from the needle to the roller is 14-16 cm, the receiving speeds of the roller are 300 rpm, 600 rpm, and 900 rpm respectively, and the spinning time is 3h-4h.

[0067] In one embodiment of the present application, photodynamic antibacterial fiber membranes with different orientation degrees were prepared by electrospinning technology. As the rotation speed of the spinning collection drum increased from 300 rpm to 900 rpm, the orientation degree increased from 63% to 87%.

[0068] In one embodiment of the present application, the crystallinity of the antibacterial fiber membrane is changed by isothermal crystallization treatment of the photodynamic antibacterial fiber membrane. As the subsequent isothermal crystallization time increases from 0 min to 90 min, the crystallinity also increases from 14.3% to 53.9%.

[0069] In one embodiment of the present application, the singlet oxygen indicator 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA) was used to detect the active oxygen yield of different antibacterial fiber membranes, reflecting that different orientations and crystal structures have different degrees of rigid restriction on the AIE photosensitive molecules contained therein.

[0070] In one embodiment of the present application, the prepared photodynamic antibacterial fiber membrane simulates the outermost layer of a mask to test its antibacterial effect on Gram-positive bacteria - Staphylococcus aureus and Gram-negative bacteria - Escherichia coli, reflecting the broad-spectrum bactericidal property of the antibacterial fiber membrane.

[0071] In a specific embodiment, when the crystallinity is regulated in the embodiment of the present application, the crystallization temperature is preferably 125-130°C, and the crystallization time is preferably 0 min, 30 min, 60 min and 90 min.

[0072] In a second aspect, an embodiment of the present application provides a photodynamic antibacterial fiber membrane prepared by the method described in the first aspect.

[0073] In a third aspect, an embodiment of the present application provides a use of the photodynamic antibacterial fiber membrane prepared by the method described in the first aspect or the photodynamic antibacterial fiber membrane described in the second aspect in preparing a polymer material.

[0074] The technical method of the present application will be further described below in conjunction with specific embodiments.

[0075] Example 1

[0076] This embodiment provides a method for preparing antibacterial fiber membranes with different orientation degrees, and the specific steps are as follows:

[0077] (1) dissolving the aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution:

[0078] 6 mg of DPA-SCP molecules were weighed and added into 1.2 mL of dimethyl sulfoxide (DMSO) solution, and ultrasonicated for 5 min at room temperature to completely dissolve the DPA-SCP molecules to obtain a photosensitive molecule solution.

[0079] (2) dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution:

[0080] 1 g of L-polylactic acid pellets was added to 20 mL of chloroform solvent to prepare a 50 mg / mL solution. The magnetic speed was 1800 rpm and the stirring temperature was 25°C. After stirring until completely dissolved, the mixed solution was aspirated with a dropper and injected into 200 mL of methanol solution for precipitation and continued stirring. After the precipitate was precipitated, it was soaked again with methanol solution and then taken out and placed in a clean glass culture dish. Tin foil was covered on the culture dish and small holes were poked in the tin foil. The culture dish was placed in a vacuum oven at 55°C for 24 hours and then taken out to obtain the purified L-polylactic acid raw material, that is, the purified polymer.

[0081] Weigh 600 mg of purified L-polylactic acid and add it to 4.8 mL of chloroform solvent to prepare a 100 mg / mL solution. The magnetic speed is 1800 rpm and the stirring temperature is 25°C. After stirring until completely dissolved, mix the prepared 1.2 mL of photosensitive molecule solution with it and continue stirring until uniform to obtain a spinning precursor solution.

[0082] (3) The spinning precursor solution is oriented by electrospinning to obtain a fiber membrane:

[0083] Pour the prepared spinning precursor liquid into a 10mL syringe, and select a 23G needle with an inner diameter of 0.6mm; the spinning voltage is 20kV, the propulsion speed is 1.0mL / h, the distance from the needle to the roller receiving is 15cm, the roller receiving speed is 300rpm, the receiving substrate is release paper, and the spinning time is 4h to prepare a photodynamic antibacterial fiber membrane.

[0084] The present application obtains antibacterial fiber membranes with different orientation degrees by changing the roller receiving speed, namely 600 rpm and 900 rpm respectively.

[0085] The obtained fiber membrane was placed in an oven at 60° C. and dried for 24 h to remove the residual solvent, thereby obtaining antibacterial fiber membranes with different orientation degrees.

[0086] The prepared antibacterial fiber membranes with different orientation degrees were peeled off from the release paper, and the orientation degrees of the antibacterial fiber membranes with different orientation degrees were characterized using an 18KW rotating target X-ray diffractometer. The instrument model was D / max-2550VB+ / PC. Figure 3 As shown, Figure 3 The scanning electron microscope image and diameter statistical graph of the antibacterial fiber membrane prepared in Example 1 at a drum speed of 900 rpm.

[0087] according to Figure 3 It can be seen that the electrospun antibacterial fiber membrane collected at a drum speed of 900 rpm is uniform in thickness and has obvious orientation, and the diameter of a single fiber is distributed in the range of 300-600 nm.

[0088] Example 2

[0089] This embodiment 2 provides a method for preparing a photodynamic antibacterial fiber membrane, and the specific steps are as follows:

[0090] The high-orientation antibacterial fiber membrane prepared in Example 1 when the receiving drum speed was 900 rpm was peeled off from the release paper, wrapped with tin foil and placed on a 130°C hot stage for isothermal crystallization for 0 min, 30 min, 60 min, and 90 min. The crystallinity of the fiber membrane was tested using an in-situ electrochemical test X-ray diffractometer, the instrument model was D8Advance / D8Advance, and the crystallinity of the fiber membrane at different isothermal crystallization times was as follows: Figure 4 shown. Figure 4 This is a characterization diagram of the crystallinity of the photodynamic antibacterial fiber membrane of Example 2 at different isothermal crystallization times.

[0091] according to Figure 4 It can be seen that with the increase of isothermal crystallization time, the crystallinity of the antibacterial fiber membrane continues to increase. The crystallinity of the antibacterial fiber membrane after isothermal crystallization for 0min, 30min, 60min and 90min are 14.3%, 37.7%, 44.9% and 53.9%, respectively.

[0092] Figure 5 The water contact angle diagram of the photodynamic antibacterial fiber membrane of Example 2 at a receiving drum speed of 900 rpm and after isothermal crystallization for 0 min and 90 min respectively.

[0093] according to Figure 5 It can be seen that the hydrophilicity and hydrophobicity of the photodynamic antibacterial fiber membrane did not change significantly before and after crystallization, and the water contact angle remained at about 138°.

[0094] In order to verify the active oxygen yield of the antibacterial fiber membranes and photodynamic antibacterial fiber membranes with different orientations prepared in Examples 1-2 of the present application, the active oxygen yield of the antibacterial fiber membranes and photodynamic antibacterial fiber membranes with different orientations provided in the examples of the present application was characterized. The results are as follows: Figure 6 shown. Figure 6 The singlet oxygen yield data graph of the low-oriented and low-crystalline antibacterial fiber membrane prepared in Example 1 with a receiving roller speed of 300 rpm and without isothermal crystallization treatment, and the high-oriented and high-crystalline photodynamic antibacterial fiber membrane in Example 2 with a receiving roller speed of 900 rpm and isothermal crystallization for 90 minutes after 12 minutes of simulated sunlight irradiation.

[0095] In this application, the fiber membranes prepared in Example 1 and Example 2 were cut into samples of 2.5 cm × 2.5 cm size for characterization of active oxygen yield. The indicator used was the singlet oxygen indicator 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA), and its characterization principle is: ABDA can react with singlet oxygen, and the concentration of the indicator decreases, resulting in a decrease in its ultraviolet absorbance. It was dissolved in DMSO solution to prepare a 25 μM mother solution, and then diluted with deionized water to 5×10 -5 Each sample was placed in 2 mL of the indicator and irradiated with an illumination of 80 mW / cm 2 The sample was irradiated with a white light source simulating sunlight for 12 minutes, and the difference between the UV absorbance after irradiation and the original absorbance was compared. The UV spectrophotometer model used was Lanbda A35.

[0096] according to Figure 6 It can be seen that the decrease in ultraviolet absorbance of the high-oriented and high-crystalline antibacterial fiber membrane after 12 minutes of simulated sunlight irradiation at a receiving speed of 900 rpm and isothermal crystallization for 90 minutes is much greater than that of the low-oriented and low-crystalline antibacterial fiber membrane at a receiving speed of 300 rpm without isothermal crystallization treatment, indicating that the restrictive effect of orientation and crystal structure on the photosensitizer molecules significantly increases its active oxygen yield.

[0097] In order to verify the photostability of the photodynamic antibacterial fiber membrane prepared in Example 2 of the present application, the photostability of the photodynamic antibacterial fiber membrane prepared in Example 2 was verified. The results are as follows: Figure 7 As shown, Figure 7 This is a data graph of singlet oxygen yield of the photodynamic antibacterial fiber membrane of Example 2 when the receiving drum speed is 900 rpm, isothermal crystallization is 90 min, and 11 cycles of irradiation are performed.

[0098] The photodynamic antibacterial fiber membrane sample with a drum collection speed of 900 rpm and a crystallization time of 90 min in Example 2 was selected, and the indicator used was the singlet oxygen indicator with the same concentration and dosage as in Example 2. The same antibacterial fiber membrane sample was subjected to 11 cycles of irradiation and singlet oxygen yield detection. The light source used in each cycle was a radiation illumination of 80 mW / cm 2 The irradiation time of each cycle is 12 minutes.

[0099] according to Figure 7 It can be seen that after 11 irradiation cycles, there is no obvious change in the decrease in the absorbance of the ABDA indicator, and it can still be maintained at 80% of the initial value, that is, the singlet oxygen yield of the sample can still be maintained at the initial level under multiple cycles of illumination, indicating that the highly crystalline and highly oriented antibacterial fiber membrane prepared in this application has excellent photostability.

[0100] Three groups of samples were used for control experiments: pure PLLA electrospun fiber membrane, antibacterial fiber membrane without isothermal crystallization treatment and receiving roller speed of 300 rpm, and antibacterial fiber membrane with 90 min isothermal crystallization treatment and receiving roller speed of 900 rpm (specification: 2.5 cm × 2.5 cm). 6 A bacterial solution with a CFU / mL concentration was used to simulate bacterial aerosols in the environment. 50 μL of bacterial solution was sprayed on each sample, and then the sample was exposed to simulated sunlight (80 mW cm -2 After 15 minutes under white light, the sample was placed in a constant temperature and humidity chamber at 37°C for 24 hours. Then, the bacteria on the membrane surface were collected with PBS buffer, and after culturing at 37°C for 24 hours, the number of colonies in each group was observed by coating with a conventional plate. Figure 8 This is a characterization diagram of the antibacterial effect of pure electrospun fiber membrane, antibacterial fiber membrane with a receiving roller speed of 300 rpm without isothermal crystallization treatment, and antibacterial fiber membrane with a 90-min isothermal crystallization treatment and a receiving roller speed of 900 rpm on Staphylococcus aureus and Escherichia coli.

[0101] according to Figure 8 It can be seen that pure PLLA electrospun fiber membrane and antibacterial fiber membrane without isothermal crystallization treatment did not show obvious antibacterial effect, while the highly oriented and highly crystallized antibacterial fiber membrane showed obvious antibacterial effect against Staphylococcus aureus and Escherichia coli under light conditions, reflecting the broad-spectrum photodynamic sterilization performance of the antibacterial fiber membrane.

[0102] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing a photodynamic antibacterial fiber membrane, characterized in that: include: dissolving the aggregation-induced luminescence photosensitive molecules in a first solvent to obtain a photosensitive molecule solution; Dissolving the purified polymer in a second solvent, and adding the photosensitive molecule solution to obtain a spinning precursor solution; The spinning precursor solution is oriented and regulated by electrostatic spinning to obtain a fiber membrane; The crystallinity of the fiber membrane is regulated to obtain a photodynamic antibacterial fiber membrane.

2. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The polymer is L-polylactic acid, and the structural formula of the L-polylactic acid is:

3. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The structural formula of the aggregation-induced luminescence photosensitive molecule is:

4. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The first solvent is one or more of dimethyl sulfoxide and N,N-dimethylformamide; And / or, the second solvent is one or more of chloroform and dichloromethane.

5. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The content of the polymer in the spinning precursor solution is 8-12 wt %; the content of the aggregation-induced luminescence photosensitive molecules in the spinning precursor solution is 1-2 wt %.

6. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The volume ratio of the first solvent to the second solvent is 1:

4.

7. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: The orientation degree regulation by electrospinning includes: the spinning voltage is 18-22 kV, the propulsion speed is 0.8-1.2 mL / h, the receiving distance from the needle to the roller is 14-16 cm, the receiving speed of the roller is 300 rpm, 600 rpm, 900 rpm, and the spinning time is 3h-4h.

8. The method for preparing the photodynamic antibacterial fiber membrane according to claim 1, characterized in that: When the crystallinity is controlled, the crystallization temperature is 125-130° C., and the crystallization time is 0 min, 30 min, 60 min and 90 min.

9. A photodynamic antibacterial fiber membrane prepared by any method according to claims 1-8.

10. Use of the photodynamic antibacterial fiber membrane prepared by any of the methods described in claims 1 to 8 or the photodynamic antibacterial fiber membrane described in claim 9 in preparing functional materials.

Images